scholarly journals Improvement of rice blast resistance by developing monogenic lines, two-gene pyramids and three-gene pyramid through MAS

Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Wuming Xiao ◽  
Qiyun Yang ◽  
Ming Huang ◽  
Tao Guo ◽  
Yongzhu Liu ◽  
...  
Keyword(s):  
Rice Blast ◽  
Agronomic Traits ◽  
Blast Resistance ◽  
Field Conditions ◽  
Blast Disease ◽  
Recurrent Parent ◽  
Panicle Blast ◽  
Gene Pyramid ◽  
High Level ◽  
Resistance Spectrum

Abstract Background Rice blast caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases in rice production. Development of resistant varieties through pyramiding of resistant (R) genes is considered as an effective strategy to cope with the disease. However, is it really essential to pyramid more R genes in a specific ecological regions? To answer this question, a set of rice improved lines were developed in this study. Afterwards, the blast disease resistance and agronomic traits of the recurrent parent (RP), donor parents (DPs) and improved lines were investigated. Results We developed seven improved lines, comprising three monogenic lines, three two-gene pyramids and one three-gene pyramid, by introgression of R gene(s) into a common genetic background using marker-assisted backcross breeding (MABB). Based on 302 SSR markers, the recurrent genome of the seven improved lines reached a range of 89.1 to 95.5%, with the average genome recovery of 92.9%. The pathogenicity assays inoculated with 32 different blast isolates under artificial conditions showed that the resistance spectrum of all the improved lines was significantly broadened. The assays further showed that the two-gene pyramids and the three-gene pyramid exhibited wider resistance spectrum than the monogenic lines. At natural nurseries, the three monogenic lines still showed high ratios of infected panicles, whereas the two-gene pyramids and the three-gene pyramid showed high level of panicle blast resistance. However, the two-gene pyramid R504 reached the similar resistance effect of the three-gene pyramid R507 considering resistance spectrum under artificial conditions and panicle blast resistance under field conditions. Generally, the improved lines showed comparable agronomic traits compared with the recurrent parent (RP), but the three-gene pyramid showed reduced grain yield per plant. Conclusions All the improved lines conferred wider resistance spectrum compared with the RP. Yet, the three monogenic lines did not work under field conditions of the two nurseries. Given the similar performances on the main agronomic traits as the RP, the two-gene pyramids have achieved the breeding goals of broad resistance spectrum and effective panicle blast resistance. Whereas, the three-gene pyramid harboring Pi2, Pi46 and Pita seems superfluous considering its reduced yield, although it also showed displayed high level of blast resistance. Thus, rational use of R genes rather than stacking more R genes is recommended to control the disease.

scholarly journals Improvement of Stable Restorer Lines for Blast Resistance through Functional Marker in Rice (Oryza sativa L.)

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1266
Author(s):  
Jegadeesan Ramalingam ◽  
Savitha Palanisamy ◽  
Ganesh Alagarasan ◽  
Vellaichamy Gandhimeyyan Renganathan ◽  
Ayyasamy Ramanathan ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Agronomic Traits ◽  
Oryza Sativa L ◽  
Blast Resistance ◽  
Dominant Gene ◽  
Development Program ◽  
Functional Marker ◽  
Blast Disease ◽  
Recurrent Parent ◽  
Back Cross

Two popular stable restorer lines, CB 87 R and CB 174 R, were improved for blast resistance through marker-assisted back-cross breeding (MABB). The hybrid rice development program in South India extensively depends on these two restorer lines. However, these restorer lines are highly susceptible to blast disease. To improve the restorer lines for resistance against blasts, we introgressed the broad-spectrum dominant gene Pi54 into these elite restorer lines through two independent crosses. Foreground selection for Pi54 was done by using gene-specific functional marker, Pi54 MAS, at each back-cross generation. Back-crossing was continued until BC3 and background analysis with seventy polymorphic SSRs covering all the twelve chromosomes to recover the maximum recurrent parent genome was done. At BC3F2, closely linked gene-specific/SSR markers, DRRM-RF3-10, DRCG-RF4-8, and RM 6100, were used for the identification of fertility restoration genes, Rf3 and Rf4, along with target gene (Pi54), respectively, in the segregating population. Subsequently, at BC3F3, plants, homozygous for the Pi54 and fertility restorer genes (Rf3 and Rf4), were evaluated for blast disease resistance under uniform blast nursery (UBN) and pollen fertility status. Stringent phenotypic selection resulted in the identification of nine near-isogenic lines in CB 87 R × B 95 and thirteen in CB 174 R × B 95 as the promising restorer lines possessing blast disease resistance along with restoration ability. The improved lines also showed significant improvement in agronomic traits compared to the recurrent parents. The improved restorer lines developed through the present study are now being utilized in our hybrid development program.

scholarly journals Improving rice blast resistance of Feng39S through molecular marker-assisted backcrossing

Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Dabing Yang ◽  
Jianhao Tang ◽  
Di Yang ◽  
Ying Chen ◽  
Jauhar Ali ◽  
...  
Keyword(s):  
Genetic Background ◽  
Rice Blast ◽  
Agronomic Traits ◽  
Blast Resistance ◽  
Snp Array ◽  
Recurrent Parent ◽  
Background Selection ◽  
Rice Blast Resistance ◽  
Major Resistance Genes ◽  
Marker Assisted Backcrossing

Abstract Background Rice blast caused by Magnaporthe oryzae is one of the most widespread biotic constraints that threaten rice production. Using major resistance genes for rice blast resistance improvement is considered to be an efficient and technically feasible approach to achieve optimal grain yield. Results We report here the introgression of the broad-spectrum blast resistance gene Pi2 into the genetic background of an elite PTGMS line, Feng39S, for enhancing it and its derived hybrid blast resistance through marker-assisted backcrossing (MABC) coupled with genomics-based background selection. Two PTGMS lines, designated as DB16206–34 and DB16206–38, stacking homozygous Pi2 were selected, and their genetic background had recurrent parent genome recovery of 99.67% detected by the SNP array RICE6K. DB16206–34 and DB16206–38 had high resistance frequency, with an average of 94.7%, when infected with 57 blast isolates over 2 years, and the resistance frequency of their derived hybrids ranged from 68.2% to 95.5% under inoculation of 22 blast isolates. The evaluation of results under natural blast epidemic field conditions showed that the selected PTGMS lines and their derived hybrids were resistant against leaf and neck blast. The characterizations of the critical temperature point of fertility-sterility alternation of the selected PTGMS lines, yield, main agronomic traits, and rice quality of the selected PTGMS lines and their hybrids were identical to those of the recurrent parent and its hybrids. DB16206–34/9311 or DB16206–38/9311 can be used as a blast-resistant version to replace the popular hybrid Fengliangyou 4. Likewise, DB16206–34/FXH No.1 or DB16206–38/FXH No.1 can also be used as a blast-resistant version to replace another popular hybrid Fengliangyou Xiang 1. Conclusions Our evaluation is the first successful case to apply MABC with genomics-based background selection to improve the blast resistance of PTGMS lines for two-line hybrid rice breeding.

Marker-assisted development and evaluation of monogenic lines of rice cv. Kaohsiung 145 carrying blast resistance genes

Plant Disease ◽  
2021 ◽  
Author(s):  
Yi-Chia Chen ◽  
Chih-Chieh Hu ◽  
Fang-Yu Chang ◽  
Chieh-Yi Chen ◽  
Wei-Lun Chen ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Agronomic Traits ◽  
Blast Resistance ◽  
Natural Infection ◽  
Durable Resistance ◽  
Recurrent Parent ◽  
Japonica Rice ◽  
Sequencing Analysis ◽  
Blast Resistance Genes

Rice blast is a serious threat to global rice production. Large-scale and long-term cultivation of rice varieties with a single blast resistance gene usually leads to breakdown of resistance. To effectively control rice blast in Taiwan, marker-assisted backcrossing was conducted to develop monogenic lines carrying different blast resistance genes in the genetic background of an elite japonica rice cultivar, ‘Kaohsiung 145’ (KH145). Eleven International Rice Research Institute (IRRI)-bred blast-resistant lines (IRBLs) showing broad-spectrum resistance to local Pyricularia oryzae isolates were used as resistance donors. Sequencing analysis revealed that the recurrent parent, KH145, does not carry known resistance alleles at the target Pi2/9, Pik, Pita, and Ptr loci. For each IRBL x KH145 cross, we screened 21–370 (average of 108) plants per generation from the BC1F1 to BC3F1/BC4F1 generation. A total of 1499 BC3F2/BC4F2 lines carrying homozygous resistance alleles were selected and self-crossed for 4–6 successive generations. The derived lines were also evaluated for background genotype using genotyping by sequencing, for blast resistance under artificial inoculation and natural infection conditions, and for agronomic performance in multiple field trials. In Chiayi and Taitung blast nurseries in 2018–2020, Pi2, Pi9, and Ptr conferred high resistance, Pi20 and Pik-h moderate resistance, and Pi1, Pi7, Pik-p, and Pik susceptibility to leaf blast; only Pi2, Pi9, and Ptr conferred effective resistance against panicle blast. The monogenic lines showed similar agronomic traits, yield, and grain quality as KH145, suggesting the potential of growing a mixture of lines to achieve durable resistance in the field.

scholarly journals Understanding Rice-Magnaporthe Oryzae Interaction in Resistant and Susceptible Cultivars of Rice under Panicle Blast Infection Using a Time-Course Transcriptome Analysis

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 301
Author(s):  
Vishesh Kumar ◽  
Priyanka Jain ◽  
Sureshkumar Venkadesan ◽  
Suhas Gorakh Karkute ◽  
Jyotika Bhati ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Metabolites ◽  
Magnaporthe Oryzae ◽  
Transcriptome Analysis ◽  
Hormonal Regulation ◽  
Rice Blast ◽  
Blast Resistance ◽  
Differentially Expressed ◽  
Specific Response ◽  
Panicle Blast

Rice blast is a global threat to food security with up to 50% yield losses. Panicle blast is a more severe form of rice blast and the response of rice plant to leaf and panicle blast is distinct in different genotypes. To understand the specific response of rice in panicle blast, transcriptome analysis of blast resistant cultivar Tetep, and susceptible cultivar HP2216 was carried out using RNA-Seq approach after 48, 72 and 96 h of infection with Magnaporthe oryzae along with mock inoculation. Transcriptome data analysis of infected panicle tissues revealed that 3553 genes differentially expressed in HP2216 and 2491 genes in Tetep, which must be the responsible factor behind the differential disease response. The defense responsive genes are involved mainly in defense pathways namely, hormonal regulation, synthesis of reactive oxygen species, secondary metabolites and cell wall modification. The common differentially expressed genes in both the cultivars were defense responsive transcription factors, NBS-LRR genes, kinases, pathogenesis related genes and peroxidases. In Tetep, cell wall strengthening pathway represented by PMR5, dirigent, tubulin, cell wall proteins, chitinases, and proteases was found to be specifically enriched. Additionally, many novel genes having DOMON, VWF, and PCaP1 domains which are specific to cell membrane were highly expressed only in Tetep post infection, suggesting their role in panicle blast resistance. Thus, our study shows that panicle blast resistance is a complex phenomenon contributed by early defense response through ROS production and detoxification, MAPK and LRR signaling, accumulation of antimicrobial compounds and secondary metabolites, and cell wall strengthening to prevent the entry and spread of the fungi. The present investigation provided valuable candidate genes that can unravel the mechanisms of panicle blast resistance and help in the rice blast breeding program.

scholarly journals Long Non-coding RNAs Responsive to Blast Fungus Infection in Rice

Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Lan-Lan Wang ◽  
Jing-Jing Jin ◽  
Li-Hua Li ◽  
Shao-Hong Qu
Keyword(s):  
Rice Blast ◽  
Blast Resistance ◽  
Enrichment Analysis ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Blast Disease ◽  
Fungus Infection ◽  
Blast Fungus ◽  
Gene Transcription Level ◽  
Non Coding Rnas

Abstract Background Long non-coding RNAs (LncRNAs) have emerged as important regulators in many physiological processes in plant. By high-throughput RNA-sequencing, many pathogen-associated LncRNAs were mapped in various plants, and some of them were proved to be involved in plant defense responses. The rice blast disease caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases in rice. However, M. oryzae-induced LncRNAs in rice is yet to be studied. Findings We investigated rice LncRNAs that were associated with the rice blast fungus. Totally 83 LncRNAs were up-regulated after blast fungus infection and 78 were down-regulated. Of them, the natural antisense transcripts (NATs) were the most abundant. The expression of some LncRNAs has similar pattern with their host genes or neighboring genes, suggesting a cis function of them in regulating gene transcription level. The deferentially expressed (DE) LncRNAs and genes co-expression analysis revealed some LncRNAs were associated with genes known to be involved in pathogen resistance, and these genes were enriched in terpenoid biosynthesis and defense response by Gene Ontology (GO) enrichment analysis. Interestingly, one of up-regulated DE-intronic RNA was derived from a jasmonate (JA) biosynthetic gene, lipoxygenase RLL (LOX-RLL). Levels of JAs were significantly increased after blast fungus infection. Given that JA is known to regulate blast resistance in rice, we suggested that LncRNA may be involved in JA-mediated rice resistance to blast fungus. Conclusions This study identified blast fungus-responsive LncRNAs in rice, which provides another layer of candidates that regulate rice and blast fungus interactions.

scholarly journals Level of Endogenous Jasmonate is Critical for Durable Broad-Spectrum Disease Resistance Against Rice Blast in a Japonica Rice Variety, Ziyu44

2021 ◽  
Author(s):  
Xingyu An ◽  
Hui Zhang ◽  
Jinlu Li ◽  
Rui Yang ◽  
Qianchun Zeng ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Signaling Pathway ◽  
Broad Spectrum ◽  
Rice Blast ◽  
Blast Resistance ◽  
Rice Variety ◽  
Blast Disease ◽  
Japonica Rice ◽  
Mycelium Growth ◽  
Broad Spectrum Resistance

Abstract Background: The molecular mechanism of durable and broad-spectrum resistance to rice blast disease in japonica rice variety is still very little known. Ziyu44, a local japonica rice variety in Yunnan Province of China, has shown durable broad-spectrum blast resistance for more than 30 years, and provides an opportunity for us to explore the molecular basis of broad-spectrum resistance to rice blast in japonica rice variety.Methods and Results: We conducted a comparative study of mycelium growth, aposporium formation, the accumulation of salicylate(SA), jasmonate(JA) and H2O2, the expression of SA- and JA-associated genes between Ziyu44 and susceptible variety Jiangnanxiangnuo (JNXN) upon M. oryzae infection. We found that appressorium formation and invasive hyphae extention were greatly inhibited in Ziyu 44 leaves compared with that in JNXN leaves. Both Ziyu 44 and JNXN plants maintained high levels of baseline SA and did not show increased accumulation of SA after inoculation with M. oryzae, while the levels of baseline JA in Ziyu 44 and JNXN plants were relatively low, and the accumulation of JA exhibited markedly increased in Ziyu 44 plants upon M. oryzae infection. The expression levels of key genes involving JA and SA signaling pathway OsCOI1b, OsNPR1, OsMPK6 as well as pathogenesis-related (PR) genes OsPR1a, OsPR1b and OsPBZ1, were markedly up-regulated in Ziyu44. Conclusions: The level of endogenous JA is critical for synchronous activation of SA and JA signaling pathway, up-regulating PR gene expression and enhancing disease resistance against rice blast in Ziyu44.

scholarly journals Osa-miR162a balances rice yield and resistance to Magnaporthe oryzae

2020 ◽  
Author(s):  
Xu-Pu Li ◽  
Xiao-Chun Ma ◽  
He Wang ◽  
Yong Zhu ◽  
Xin-Xian Liu ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Rice Blast ◽  
Rice Yield ◽  
Blast Resistance ◽  
Blast Disease ◽  
Mirna Biogenesis ◽  
Trade Off ◽  
Rice Blast Resistance ◽  
Defense Related Gene ◽  
Transgenic Lines

Abstract MicroRNAs (miRNAs) play essential roles in rice immunity against Magnaporthe oryzae, the causative agent of rice blast disease. Osa-miR162a targets Dicer-like 1 (DCL1) genes, which play vital roles in miRNA biogenesis and act as negative regulators in rice immunity. Here we demonstrate that Osa-miR162a improves rice immunity against M. oryzae and balances the trade-off between rice yield and resistance. Overexpression of Osa-miR162a compromises rice susceptibility to M. oryzae accompanying enhanced induction of defense-related genes and accumulation of hydrogen peroxide (H2O2). In contrast, blocking miR162 by overexpressing a target mimic of miR162 enhances susceptibility to blast fungus associating with compromised induction of defense-related gene expression and H2O2 accumulation. Moreover, the transgenic lines overexpressing Osa-miR162a display decreased seed setting rate resulting in reduced yield per plant, whereas blocking miR162 leads to an increased number of grains per panicle, resulting in increased yield per plant. Altered accumulation of miR162 had limited impact on the expression of OsDCL1. Together, our results indicate that Osa-miR162a improves rice blast resistance and plays a role in the balance of trade-off between resistance and yield.

Investigating the biology of rice blast disease and prospects for durable resistance

2021 ◽  
pp. 643-680
Author(s):  
Vincent M. Were ◽  
◽  
Nicholas J. Talbot ◽  
Keyword(s):  
Cell Biology ◽  
Rice Blast ◽  
Plant Pathogens ◽  
Blast Resistance ◽  
Durable Resistance ◽  
Rice Blast Disease ◽  
Blast Disease ◽  
Global Food Security ◽  
Major Resistance Genes ◽  
Effector Secretion

There are important biological process involved in rice blast disease that are now well-studied during the early events in plant infection which include: the cell biology of appressorium formation, the biology of invasive growth and effector secretion, the two distinct mechanisms of effector secretion, the nature of the plant-pathogen interface, PAMP-triggered immunity modulation by secreted effectors and effector-triggered immunity and blast resistance. The devastating losses caused by the blast fungus have been documented in most grasses, but this chapter discusses the use of major resistance genes to rice blast and wheat blast disease as an emerging threat to global food security. This chapter also highlights an emerging approach to breed for durable resistance to plant pathogens using gene editing technologies with an example: CRISPR-Cas9 mutagenesis of dominant S-genes for disease control.

scholarly journals Reaction of Different Rice Lines Against Leaf and Neck Blast under Field Condition Of Chitwan Valley

2006 ◽  
Vol 27 ◽  
pp. 37-44 ◽  
Author(s):  
KD Puri ◽  
SM Shrestha ◽  
KD Joshi ◽  
GB KC
Keyword(s):  
Field Condition ◽  
Rice Blast ◽  
Blast Resistance ◽  
Blast Disease ◽  
Resistant Variety ◽  
Pyricularia Grisea ◽  
Leaf Blast ◽  
Neck Blast ◽  
Chitwan Valley ◽  
Moderately Resistant

The severity of the rice blast disease (Pyricularia grisea) of both leaf and neck varies with different environment and it becomes destructive under favorable condition. The leaf and neck blast resistance and susceptible interaction of 30 different tropical rice lines were evaluated under low-, mid- and up-land conditions of Chitwan district and classified on the basis of disease severity with respect to susceptible check, Masuli. Of them, 5, 10, 12 and 3 rice lines were resistant to leaf blast, moderately resistant, moderately susceptible susceptible, respectively. Similarly, for the neck blast nine lines were resistant, thirteen moderately resistant, seven moderately susceptible and one was susceptible. The progenies from Masuli/MT4 had the highest leaf and neck blast susceptible reaction, while the most of progenies from IPB (Irradiated Pusa Basmati), KalinghaIII_IR64, Radha 32_ KIII and Masuli_IR64 were resistant, and the most promising sources against leaf and neck blast resistance. Therefore, the progenies from these parents can be used in breeding the resistant variety. Key words: Pyricularia grisea, resistance, rice lines J. Inst. Agric. Anim. Sci. 27:37-44 (2006)

scholarly journals Integrated strategies for durable rice blast resistance in sub-Saharan Africa

Plant Disease ◽  
2021 ◽  
Author(s):  
Samuel K Mutiga ◽  
Felix Rotich ◽  
Vincent M Were ◽  
John Kimani ◽  
David Thuranira Mwongera ◽  
...  
Keyword(s):  
Rice Blast ◽  
Crop Production ◽  
Blast Resistance ◽  
Research Effort ◽  
Rice Production ◽  
Rice Blast Disease ◽  
Sub Saharan Africa ◽  
Blast Disease ◽  
Small Scale ◽  
Sub Saharan

Rice is a key food security crop in Africa. The importance of rice has led to increasing country-specific, regional and multinational efforts to develop germplasm and policy initiatives to boost production for a more food secure continent. Currently, this critically important cereal crop is predominantly cultivated by small-scale farmers under sub-optimal conditions in most parts of sub-Saharan Africa (SSA). Rice blast disease, caused by the fungus Magnaporthe oryzae, represents one of the major biotic constraints to rice production under small-scale farming systems of Africa, and developing durable disease resistance is therefore of critical importance. In this review, we provide an overview of the major advances by a multinational collaborative research effort to enhance sustainable rice production across SSA and how it is affected by advances in regional policy. As part of the multinational effort, we highlight the importance of joint international partnerships in tackling multiple crop production constraints through integrated research and outreach programs. More specifically, we highlight recent progress in establishing international networks for rice blast disease surveillance, farmer engagement, monitoring pathogen virulence spectra, and the establishment of regionally-based blast resistance breeding programs. To develop blast resistant, high yielding rice varieties for Africa, we have established a breeding pipeline that utilizes real-time data of pathogen diversity and virulence spectra, to identify major and minor blast resistance genes for introgression into locally adapted rice cultivars. In addition, the project has developed a package to support sustainable rice production through regular stakeholder engagement, training of agricultural extension officers, and establishment of plant clinics.

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